Case Studies

Reliability and responsiveness of Dynamika parameters

A recent paper published in Scandinavian Journal of Rheumatology (M. Axelsen, M. Ostergaard, 2011) aimed to investigate the responsiveness to treatment and the reliability of DCE-MRI in RA knee joints.

In 12 clinically active RA knee joints DCE-MRI was performed before and 1, 7, 30 and 180 days after intra-articular injection with 80 mg methylprednisolone. All data was processed using Dynamika. In all patients clinical remission of the knee was achieved at day 7. All DCE-MRI parameters decreased from day 0 to day 7.

Placing a quick ROI method, we observed decrease in IRE by 69%, in ME by 11%, in a number of voxels by 57%, and the parameter IRExNvoxel decreased by 85%. The intra-and inter- reader ICCs were between 0.96 and 1.00. The decline in DCE-MRI parameters was larger comparing to the decline in the SDC for all patients.

This research concluded that DCE-MRI analyzed using Dynamika software is a reliable and responsive tool for assessing response to treatment in RA knees joints.

Correlation between Dynamika parameters and RAMRIS scores in healthy controls

In healthy controls, the erosion can be observed on MRI, but scored low with RAMRIS. Dynamika would allow drawing a ROI around the erosion and the corresponding bone to measure the volume / size of erosion in mm or relatively to the volume / size of the bone.

To score synovitis, it is important to acquire images soon after injection as with time, the synovial enhancement can be seen in healthy subjects as well. The researchers reported that the inherent variability in Dynamika measurements is small and remains stable throughout the year (P. Taylor, A. Rastogi, in preparation, 2011).

Dynamika parameters have high correlations with synovial and BME scores. Specifically, the correlation of RAMARIS synovitis with Dynamika parameters exceeded 0.82, with bone marrow – 0.84. According to this research, the automated voxel-by-voxel method incorporated into Dynamika is a strong candidate in inflammatory arthritis biomarker search and longitudinal studies.

Correlation between computer aided DCE-MRI assessment of inflammation and semiquantitative synovitis and bonemarrow oedema scores of the wrist in patients with rheumatoid arthritis.

A recent paper published in Rheumatology (Boesen, 2011) tested the correlation between assessment of inflammation using DCE-MRI analysed by a novel computer-aided approach Dynamika and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RAMRIS scoring system, in the wrist of patients with rheumatoid arthritis (RA). 54 RA patients had conventional and DCE-MRI of a symptomatic wrist using a low-field 0.2T dedicated extremity scanner. RAMRIS of synovitis (range 2-9), BME (range 0-39) and the dynamic parameters reflecting the volume of enhancing voxels were significantly correlated, especially when a extended ROI around the wrist was used; rho=0.74; p<0.01 for synovitis and rho=0.82; p<0.01 for BME. The observer spend on average 20 minutes (range 12-25) to perform the RAMRIS, including acquisition of the results in the database, and 8 minutes (range 7-10) to perform the computer aided analysis including both the fully automated, the extended ROI and the small ROI analysis. The paper concluded that computer-aided analysis of DCE-MRI data correlated with RAMRIS of synovitis and BME and was twice as fast to perform. This technique may be useful for quick semi-automated assessment of joint inflammation, but needs further validation.